These prints are the first four collotypes drawn by Michael Pickwoad (1945-2018) to mark European Architectural Heritage Year in 1975. A collotype is a dichromate-based process that uses a sheet of light-sensitive gelatine exposed photographically to the image without using a screen. Invented by Alphonse Poitevin in 1856 it was used for volume mechanical printing before offset lithography. Results can be difficult to distinguish from metal-based photographic prints. Many old postcards are collotypes. Pickwoad, an engineer, became a distinguished art director and Bafta nominee, well known as a Production Engineer in film and television.
These collotypes are 48.9 x 31.7 cm (19.2″ x 12.5″) on high white matt heavy cardstock of 200 g/sm2. Below are scans of the prints.